Project for bdsabur

I have an issue and I would like your advice on best & fastest method to update my ecommerce stores product database.

The current vitamin product database is 10 years old and I need to upload new products, modify existing products, optimize product images and alt tags, and delete products that do not sell.

The issue is that I have 100 or so different brands and various suppliers who have sent me a excel file containing basic product information such as pricing name etc but no descriptions or products images. These will need to be sourced from each brands individual website.

Can you please advise how you would update our database? Also, the website is currently being redesigned.